Process for cleaning and recovering soldered joints



' No Drawing.

Patented Mar. 3, 1925 JEAN GOUESNON, OF PARIS, FRANCE.

PSBDCISS FOR CLEARING AND RECOVERING SOLDERED JOINTS To all whom it may concern.

Be it known that I, JEAN CoUnsxoN, citizen of the Republic of France, residing-at Paris, in the Republic of France, have invented certain new and useful Improvements in Processes for Cleaning and Recovering Solde'red Joints, of which the followm is an exact and Complete description.

everal processes are already known for the cleaning and recovery of solders intended for example for the purpose of removing the dross and excrescences' from soldered joints, orfor the recovery of the metals comattending its use. 7 One well known method is an electrolytic process in which the surface to be treated is connected electrically as an anode, the metal thereby becoming more or less mits its easy remova This method has the advantage of belng very economical, the electric .current necessary requiring only a very low voltage; but while it is easy and almost ideal in its results when used for the purpose of cleaning pure metallic surfaces it will give only mediocre results when used with alloys, brass, German silver, bronzes, etc. a

With alloys it is found that themetals .composing'the alloy are affected differently, thesurface, in vplace ofbeing cleaned is destroyed, or at least partial y deteriorated.

The object of my invention is to avoid this prime defect by using as an electrolyte in the electrol'yzing bath a salt in solution capable of passin to the anode an ion which will combine with the metal to be removed, changing it into a product more'or less granular and easily detachable, while the metal below the solder or alloy remains unaffected.

When treating tin or lead, brass, for instance, it is necessary to avoid simultaneous action on the zinc of. the brass, which would leave the copper without its alloyed metal while action is taking .place with the tin or the lead. v

This result may be obtained by electrol zing a soda solution of sodium zincate un er which circumstances the zincate decomposes. The oxide travelling toward the anode would not have enough oxidizing power b itself to form the zincateof tin or of lea but the soda of the solution furnishes the balance of power necessary, and the heavy metals. are attacked, while the alloy remains untouched.

'baith. ,'.'21 The operation proccedsat a very low volt-- choose other spongy or muddy to an extent which 'per rloys having sol zinc of the Application filed February 15, 1921. Serial No. 445,189.

Naturally there is no need to prepare a' zmcate solution beforehand; all that is neccssary is to add oxide of zinc to the alkaline age. The object to be cleaned having been placed at the anode it is only necessary thereafter to wipe it off or wash it with dilute acid in order to obtain an absolutely clean surface. It will be evident that in the case of other alloys it will be necessary to lyte (aluminate for aluminum, taking care to observe the principle of my invention, which is to bring about the decomposition of the salt of which the anion attacks the. metal of the solder or of the dross, without having a tendency to attack joints, thus obviating the need of nickelplating the outside of-soldered pieces, the real purpose of which is to cover up all defects. In this case, on'the contrary, the object is finished with an absolutely clean joint, and, if the soldered surfaces have been proper] "prepared so that the joint is. tight it will e invisible. Moreover, nickel plating, in the particular case of zincate electrolyte, may be replaced by. the de osit of oxide of zinc which forms on all 0 the metallic surfaces exposed, and which is capable of taking a certain amount of polish.

I claim: 1. An electrolytic process for cleaning alered portions, by means of an electrolyte containing a salt the anion of which is capable of attacking the metals composing the solder without attacking the metals of the alloy. 2. An electrolytic process for cleaning objectshavin soldered portions which con- 'sists in intro ucing the article as an anode electrolyte containing a 'zin- Witness Amour Mom'an.rmr.

suitable salts for the electro-' bronze, etc.)

JEAN oouEsNo u. 7 

